JP5901251B2 - Manufacturing method of structure - Google Patents

Description

  The present invention relates to a method for manufacturing a structure, and more particularly, to a method for manufacturing a structure having a hollow portion by laminating members to be joined.

  Structures in which aluminum alloy plate materials, other metal plates, and nonmetal plates are laminated are widely used in heat exchangers and the like (see, for example, Patent Documents 1 and 2). For example, a plurality of metal base plates such as SUS and aluminum alloy plates and ceramics, such as ceramics, are laminated in the thickness direction of the plate, and at least one of the base plates has a fine surface. A structure in which a channel for supplying a heating fluid or a cooling fluid is formed is manufactured by forming a groove and joining the surface on which the groove is formed and the flat surface of the adjacent base plate. Conventionally, brazing (for example, refer to Patent Documents 3 and 4), solid phase diffusion bonding (for example, refer to Patent Documents 3 to 5 and Non-Patent Document 1), ultrasonic bonding, adhesive bonding, and the like are known for bonding materials. ing. Here, the solid phase bonding method such as the diffusion bonding method or the friction bonding method is a bonding method that does not involve melting of the members to be bonded in principle. In the diffusion bonding method, the base materials are brought into close contact with each other, basically pressed to the extent that the plastic deformation does not occur below the melting point of the base material, and bonding is performed using the diffusion of atoms generated between the joint surfaces. A structure having a hollow portion such as a flow path may be manufactured by a casting / die casting method typified by a sand mold casting method.

Japanese Patent Laid-Open No. 3-51696 JP-A-4-217792 JP 2001-349679 A JP 2010-164244 A Japanese Patent Laid-Open No. 2003-247796 Japanese Patent Application Laid-Open No. 5-30559 Japanese Patent No. 3656092

Mitsumasa Sakamoto, Yuki Tsuzuki, Hideki Morigo, Yuu Kobayashi, Kazuo Kusaka, “Development of variable thrust injectors for space equipment using precision diffusion bonding technology”, Mitsubishi Heavy Industries, vol. 37, no. 3, pp. 134-137, May 2000

  When manufacturing a structure having a three-dimensional flow path, if multiple members are joined using brazing or soldering material, the flow path may be clogged by molten brazing material or soldering material. is there. In addition, unevenness may be formed on the inner wall surface of the flow path due to the remaining braze fillet or solder material at the joint location, and the cross-sectional area in the flow path may be reduced. In such a case, there arises a problem that the desired heat exchange performance of the integrally laminated heat exchanger cannot be obtained.

  When the diffusion bonding method is used, multipoint bonding and surface bonding can be performed simultaneously without deformation of the members to be bonded. Therefore, it is possible to join the members to be joined having a fine shape. However, the diffusion bonding method usually requires holding at a predetermined temperature for about 30 minutes or more, and it takes a long time for bonding compared to bonding by welding or brazing. In addition, in the diffusion bonding method, in order to obtain a laminated plate, the flow path members are laminated, and the upper and lower sides are pressurized and heated in a vacuum atmosphere. Therefore, pressure is required for the bonding, which complicates the bonding operation and costs. An increase is inevitable. In addition, since aluminum alloy materials have a stable and strong oxide film on the surface and diffusion is hindered, it is necessary to perform a cleaning process to remove the oxide film on the bonding surface, which causes argon ion bombardment, glow There are cases where special processes such as discharge and application of ultrasonic waves are required. Further, in the diffusion bonding method, it is necessary to perform a treatment such as plating depending on the type of material to be bonded. Furthermore, when metal plates are joined by the diffusion joining method, defects such as voids may occur on the joining surface, making it difficult to obtain a desired structure.

  The friction stir welding method applied to the aluminum material among the friction welding methods can be applied to all aluminum alloy materials. The friction stir welding method has an advantage that deformation of a member to be joined due to joining is small because the base material is not melted. However, although a partial overlap bonding is possible, it is basically a construction method used for butt joining, and the shape of the joint is limited to a straight line or a gentle curve, and it is difficult to join complicated shapes. In addition, since the joining tool is brought into direct contact with the joining portion, it is difficult to join the fine shapes, and it is also difficult to join multiple points at the same time. Moreover, in this joining method, the mark of a joining pin will remain in a joining termination part.

  In castings represented by the sand mold casting method, it is necessary to remove the sand from the core. For example, a hollow portion having a complicated shape such as a spiral shape makes it difficult to mold the core. In addition, it is conceivable to manufacture the structure by machining such as cutting and drilling, but it is difficult to obtain a complicated hollow portion. Furthermore, it is conceivable to manufacture the structure by lamination by adhesion, but there is a possibility that sufficient strength cannot be obtained because it does not have a metal bond.

  An object of this invention is to manufacture easily the structure which has a hollow part.

In order to solve the above-mentioned problem, a manufacturing method of a structure according to the first aspect of the present invention is a method of manufacturing a structure having a hollow portion by laminating members to be joined,
A step of preparing an aluminum alloy plate having a magnesium content of 0.5% by mass or less and a cutout portion formed as at least a part of the members to be joined;
A plurality of the members to be bonded are stacked so that at least one of the adjacent members to be bonded becomes the aluminum alloy plate and the cutout portion communicates to form the hollow portion. A step of joining a plurality of the members to be joined in a temperature range in which the mass ratio of the liquid phase is 5% or more and 35% or less within 30 seconds to 3600 seconds;
Only including,
In the step of joining the members to be joined, the maximum stress generated in the aluminum alloy material generating the liquid phase is P (kPa), and the ratio of the mass of the liquid phase generated in the aluminum alloy plate is V (%). Sometimes, the members to be joined are joined under the condition satisfying P ≦ 460-12 × V.
It is characterized by that.

The method for manufacturing a structure according to the second aspect of the present invention is a method for manufacturing a structure having a hollow portion by laminating members to be joined,
A step of preparing an aluminum alloy plate having a magnesium content of 0.2% by mass or more and 2.0% by mass or less and having a cut-out portion formed as at least a part of the bonded members;
A plurality of the members to be bonded are stacked so that at least one of the adjacent members to be bonded becomes the aluminum alloy plate and the cutout portion communicates to form the hollow portion. A step of joining a plurality of the members to be joined in a temperature range in which the mass ratio of the liquid phase is 5% or more and 35% or less within 30 seconds to 3600 seconds;
Only including,
In the step of joining the members to be joined, the maximum stress generated in the aluminum alloy material generating the liquid phase is P (kPa), and the ratio of the mass of the liquid phase generated in the aluminum alloy plate is V (%). Sometimes, the members to be joined are joined under the condition satisfying P ≦ 460-12 × V.
It is characterized by that.

In the step of preparing the member to be joined, a disk-shaped member having the same shape having the cutout portion is prepared as the member to be joined,
In the step of bonding the members to be bonded, a plurality of the members to be bonded may be stacked while shifting the phase of the cutout portion.

  According to the present invention, a structure having a hollow portion can be easily manufactured.

It is a figure which shows typically the phase diagram of an Al-Si alloy as a binary eutectic alloy. It is explanatory drawing which shows the production | generation mechanism of the liquid phase in the aluminum alloy material which concerns on this embodiment. It is a front view which shows the observation surface position of a reverse T-shaped joining test piece and its junction part. It is a microscope picture which expands and shows the junction part in FIG. In Example 1, it is a figure for demonstrating the process of laminating | stacking a some to-be-connected member and manufacturing a structure. In Example 2, it is a figure for demonstrating the process of laminating | stacking a to-be-connected member and manufacturing a structure. In Example 3, it is a figure for demonstrating the process of laminating | stacking a to-be-connected member and manufacturing a structure.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

A. Combination of members to be joined In the structure manufacturing method according to this embodiment, an aluminum alloy material is used as one member to be joined, and any one of an aluminum alloy material, a pure aluminum material, and a metal material other than aluminum is used as the other member to be joined. As described above, one member to be joined and the other member to be joined are joined. When joining aluminum alloy materials, those with the same alloy composition or those with different alloy compositions may be used.

B. Generation of Liquid Phase In the method for manufacturing a structure according to this embodiment, the ratio of the mass of the liquid phase generated in the aluminum alloy material to the total mass of the aluminum alloy material that is one member to be joined (hereinafter referred to as “liquid phase”). Bonding is performed at a temperature at which 5% to 35%. When the liquid phase ratio exceeds 35%, the amount of the liquid phase to be generated is too large and the aluminum alloy material starts to melt. On the other hand, bonding is not possible unless a liquid phase is generated. The preferable liquid phase rate at the time of joining plate materials is 5 to 30%, and the more preferable liquid phase rate is 10 to 20%.

  It is extremely difficult to measure the actual liquid phase ratio during heating. Therefore, the liquid phase ratio defined in this embodiment is obtained by equilibrium calculation. Specifically, the temperature is calculated from the alloy composition and the highest temperature achieved during heating by thermodynamic equilibrium calculation software such as Thermo-Calc.

  The generation mechanism of the liquid phase will be described. FIG. 1 is a diagram schematically showing a phase diagram of an Al—Si (aluminum silicon) alloy which is a typical binary eutectic alloy. As shown in FIG. 1, when an aluminum alloy material whose Si concentration is higher than the maximum solid solution limit concentration c1 is heated, a liquid phase is generated at a temperature T1 near the eutectic temperature (solidus temperature) Te. Begins. Below the eutectic temperature Te, as shown in FIG. 2A, crystal precipitates are distributed in the matrix divided by the grain boundaries. Here, when the generation of the liquid phase starts, as shown in FIG. 2B, the crystal grain boundary with a large segregation of the crystal precipitate distribution melts to become a liquid phase. Next, as shown in FIG. 2C, the periphery of the Si crystal precipitate particles and intermetallic compounds, which are the main additive element components dispersed in the matrix of the aluminum alloy, melts into a spherical shape to form a liquid phase. Further, as shown in FIG. 2 (d), this spherical liquid phase generated in the matrix is re-dissolved in the matrix with the passage of time and temperature due to the interfacial energy, and the grain boundaries and the surface are diffused by diffusion in the solid phase. Move to. And when temperature rises to temperature T2 higher than temperature T1, liquid phase amount will increase. In addition, as shown in FIG. 1, when the Si concentration of one aluminum alloy material is a concentration c2 smaller than the maximum solid solubility limit, generation of a liquid phase starts near the solidus temperature Ts2. However, unlike the case where the Si concentration shown in FIG. 2A is the concentration c1, there may be a case where small precipitate particles are not present in the matrix in the structure immediately before melting. In this case, as shown in FIG. 2 (b), the melt first melts at the grain boundary to form a liquid phase, and then the liquid is more liquid than the locally high solute element concentration in the matrix as shown in FIG. 2 (c). A phase occurs. This spherical liquid phase generated in the matrix is re-dissolved in the matrix with the passage of time and temperature due to the interfacial energy as in the case where the Si concentration is the concentration c1, and the grain boundary and the surface are formed by diffusion in the solid phase. Move to. And when temperature rises to temperature T3 higher than temperature Ts2, liquid phase amount will increase. As described above, the structure manufacturing method according to this embodiment uses a liquid phase generated by partial melting inside the aluminum alloy material, and can realize both the joining and shape maintenance of the members to be joined. Is.

C. Behavior of metal structure in joining The behavior of the metal structure after the liquid phase occurs until joining is explained. As shown in FIG. 3, an inverted T-shaped test piece using an aluminum alloy material A that generates a liquid phase and an aluminum alloy material B to be bonded to the liquid phase is bonded, and the bonding location is observed with a microscope. (See FIG. 3). As described above, the very slight liquid phase generated on the surface of one aluminum alloy material A fills the gap with the other aluminum alloy material B in which the oxide film is destroyed by the action of flux or the like. Next, the liquid phase of the aluminum alloy material A in the vicinity of the joint interface between the two alloy materials moves into the aluminum alloy material B, and along with this movement, the solid phase of the aluminum alloy material A that is in contact with the joint interface. α-phase crystal grains grow into the aluminum alloy material B. Further, the crystal grains of the aluminum alloy material B also grow to the aluminum alloy material A side.

  In the case where the aluminum alloy material B is an alloy that does not generate a liquid phase, as shown in FIG. 4A, the structure of the aluminum alloy material A enters the aluminum alloy material B in the vicinity of the bonding interface. Aluminum alloy materials A and B are joined together. Therefore, no metal structure other than the aluminum alloy material A and the aluminum alloy material B is generated at the bonding interface. When the aluminum alloy material B is also an alloy that generates a liquid phase, as shown in FIG. 4B, both alloy materials have a completely integrated structure, and the bonding interface cannot be determined.

  On the other hand, when a brazing sheet clad with a brazing material is used as the aluminum alloy material B, a fillet is formed at the joint and a eutectic structure is seen as shown in FIG. Thus, when a brazing sheet is used as the aluminum alloy material B, a bonded structure different from the bonded structure shown in FIGS. 4A and 4B is formed. In the brazing method, a liquid phase braze fills the joint to form a fillet, so that a eutectic structure different from the surrounding is formed in the joint. Also, in the welding method, since the joint portion is locally melted, the metal structure is different from other portions. On the other hand, in the joining step of the aluminum alloy according to this embodiment shown in FIGS. 4 (a) and 4 (b), the metal structure of the joining portion is composed only of the members to be joined, or both the members to be joined. Is different from the joint structure by brazing or welding in that it is composed of an integrated structure.

  Due to such bonding behavior, the shape change in the vicinity of the bonding site hardly occurs in the bonding process according to this embodiment. That is, the shape change after joining like the bead of the welding method and the fillet by the brazing method hardly occurs in the joining process according to this embodiment. For example, when a Delon cup type laminated heat exchanger is assembled using a brazing sheet (a brazing material clad rate is 5% on one side), the molten brazing material concentrates on the joint after brazing heating, so that lamination is performed. The height of the heat exchanger is reduced by 5 to 10% due to the joining of the members. Therefore, it is necessary to consider the decrease in product design. On the other hand, in the joining process of this embodiment, the dimensional change after joining is as small as 5% or less, and high-precision product design is possible.

D. Destruction of the oxide film An oxide film is formed on the surface layer of the aluminum material, which inhibits bonding. Therefore, it is necessary to destroy the oxide film in joining. In the structure manufacturing method of this embodiment, in order to destroy the oxide film, any of the following methods D-1 or D-2 is adopted.

D-1. Destruction of oxide film by flux In this method, in order to destroy the oxide film, a flux is applied to at least the joint. As the flux, fluoride flux such as KAlF ₄ or CsAlF ₄ , chloride flux such as KCl or NaCl, or the like can be used. These fluxes melt before the liquid phase melts in the aluminum alloy lamination method, and react with the oxide film to destroy the oxide film.

  Moreover, in order to suppress formation of an oxide film, it is preferable to join in an atmosphere of a non-oxidizing gas such as nitrogen or argon. In particular, when a fluoride-based flux is used, bonding is preferably performed in a non-oxidizing gas atmosphere in which the oxygen concentration is suppressed to 250 ppm or less and the dew point is suppressed to -25 ° C. or less.

  Furthermore, when a fluoride-based flux is used, if Mg is contained in an aluminum alloy in an amount exceeding 0.5% by mass as one and the other members to be joined, the flux reacts with Mg and the oxide film of the flux Destructive action is impaired. Therefore, an aluminum alloy having a Mg content of 0.5% by mass or less is used for the member to be joined. In addition, as long as the Mg content satisfies the condition of 0.5% by mass or less, any kind and content of other elements contained in the aluminum alloy may be used.

D-2. Destruction of oxide film due to the action of Mg When Mg is added to the aluminum alloy material, the oxide film is destroyed in the joining process of the aluminum alloy material without applying flux to the joint, thus enabling bonding. . In this case, like the vacuum fluxless brazing, when the aluminum alloy melts and the liquid phase comes out to the surface layer, the oxide film on the surface is destroyed by the getter action of Mg that evaporates from the aluminum alloy.

  In the case of a method for destroying an oxide film by the action of Mg, it is preferable to use a furnace in a vacuum or a non-oxidizing atmosphere in order to suppress the formation of the oxide film. However, in the case of surface bonding or closed space bonding, bonding may be performed in a dry atmosphere. In the case of bonding in gas, it is preferable to suppress the dew point to -25 ° C or lower.

  In order to destroy the oxide film by the action of Mg, it is necessary that the aluminum alloy material contains at least 0.2 mass% and 2.0 mass% of Mg. When Mg is less than 0.2% by mass, the getter action does not work sufficiently, and the oxide film does not sufficiently bond. On the other hand, when Mg exceeds 2.0% by mass, Mg reacts with oxygen in the atmosphere on the surface of the aluminum alloy material, and a large amount of oxide MgO is generated to inhibit bonding.

E. Lower limit of time required for liquid phase formation In the bonding process of the members to be bonded according to this embodiment, after the oxide film is destroyed at the bonded portion, the liquid phase is filled between the members to be bonded and bonded. This liquid phase is generated in an aluminum alloy material which is one member to be joined. In order for the liquid phase to be sufficiently filled in the joint, the time during which the liquid phase ratio is 5% or more is preferably 30 seconds or more. More preferably, when the time of the liquid phase ratio of 5% or more is 60 seconds or more, sufficient filling is performed and reliable bonding is performed. In this joining, since the liquid phase moves only in the very vicinity of the joint, the time required for this filling does not depend on the size of the joint. Note that a liquid phase may also be generated in the aluminum alloy material that is the other member to be joined, and the time during which the liquid phase ratio is 5% or more is preferably 30 seconds or more, more preferably 60 seconds or more.

F. Upper Limit of Joining Time Required for Maintaining Shape In the joining process of the member to be joined according to this embodiment, the time during which the liquid phase ratio in the aluminum alloy material that is one member to be joined that generates a liquid phase is 5% or more is 3600. Preferably it is within seconds. If it exceeds 3600 seconds, the bonded member may be greatly deformed even if the liquid phase ratio is 35% or less. More preferably, when the time during which the liquid phase ratio is 5% or more is set within 1800 seconds, the shape change can be reliably suppressed. Even when a liquid phase is generated in the aluminum alloy material that is the other member to be bonded, the time during which the liquid phase ratio in the other member to be bonded is 5% or more is preferably within 3600 seconds, Preferably, it is within 1800 seconds.

G. Stress applied to both members to be joined at the time of joining In the joining process of the members to be joined according to this embodiment, it is not always necessary to apply pressure to the joining surfaces as long as both the members to be joined are in contact with each other at the joint. However, in an actual product manufacturing process, stress is often applied to both members to be joined by a jig or the like in order to fix the members to be joined or to reduce the clearance. Further, stress is also generated in the member to be joined by its own weight. At this time, the stress which generate | occur | produces in each site | part in each to-be-joined member is calculated | required from a shape and a load. For example, it can be calculated using a structural calculation program or the like. In this embodiment, P (kPa) is the maximum stress (maximum stress) generated in each part of the bonded member that generates a liquid phase during bonding, and the liquid phase of the aluminum alloy that is the bonded member When the rate is V (%), it is preferable to join so as to satisfy P ≦ 460-12 × V. The value shown on the right side of this equation is the critical stress, and if a stress exceeding this is applied to the member to be joined that generates a liquid phase, large deformation occurs in the member to be joined even if the liquid phase ratio is within 35%. There is a fear. In addition, when a liquid phase generate | occur | produces from both to-be-joined members, P <= 460-12 * V is calculated using each stress P and liquid phase rate V with respect to both to-be-joined members, and both to-be-joined members Both are joined so as to satisfy the above equations at the same time.

H. Alloy particularly suitable for the manufacturing method of the structure according to this embodiment As described above, in the joining step according to this embodiment, when flux is used for breaking the oxide film, as an aluminum alloy material to be joined, Mg An aluminum alloy having a content of 0.5% by mass or less is used. Moreover, when using the getter action of Mg without destroying the oxide film, the Mg content is 0.2 mass% or more and 2.0 mass% or less as an aluminum alloy material which is one member to be joined. The aluminum alloy is used. In this case, as the aluminum alloy material that is the other member to be joined, for example, an aluminum alloy having an Mg content of 2.0 mass% or less is used.

  Moreover, you may use the Al-Si alloy and Al-Si-Mg alloy which contain Si element as an essential component as an aluminum alloy material which is one to-be-joined member. In such an aluminum alloy, a Si content (mass concentration) X of 0.6 to 3.5% by mass is preferably used. When the Si content X is less than 0.6% by mass, the temperature range in which the liquid phase ratio is 5% to 35% is narrowed, and stable bonding may be difficult. On the other hand, when the Si content X exceeds 3.5% by mass, the amount of liquid phase generated at the solidus temperature (= eutectic temperature) increases, and the liquidus ratio becomes 35% from the solidus temperature. In some cases, the temperature range up to the temperature becomes narrow and stable bonding becomes difficult. The more preferable content X of Si is 1.2 to 3.0% by mass.

  The Al-Si alloy or Al-Si-Mg alloy is Cu: 0.05 to 0.5 mass%, Fe: 0.05 to 1.0 mass%, Zn: 0.2 to 1.0 mass%. %, Mn: 0.1 to 1.8% by mass and Ti: 0.01 to 0.3% by mass may be further included. That is, Mg content is 0.5 mass% or less or 0.2 mass% or more and 2.0 mass% or less, Si: 0.6-3.5 mass% is contained as an essential element, Cu: 0 0.05 to 0.5 mass%, Fe: 0.05 to 1.0 mass%, Zn: 0.2 to 1.0 mass%, Mn: 0.1 to 1.8 mass%, and Ti: 0.01 One or two or more elements selected from ˜0.3% by mass are further contained as selective additive elements, and an aluminum alloy material made of an aluminum alloy consisting of Al and inevitable impurities is suitably used.

  When an aluminum alloy material made of such an Al—Si alloy or Al—Si—Mg alloy is joined as one joined member to the other joined member, the temperature T of one joined member during joining is Si. According to the content X, it is preferable to control so that 660-39.5X <= T <= 660-15.7X and T> = 577 are satisfy | filled. This achieves even better bonding.

  Furthermore, an Al—Cu alloy or an Al—Cu—Mg alloy containing Cu element as an essential component may be used as the aluminum alloy material that is one member to be joined. In such an aluminum alloy, a Cu content (mass concentration) Y of 0.7 to 15.0 mass% is preferably used. When the Cu content Y is less than 0.7% by mass, the temperature range in which the liquid phase ratio is 5% to 35% becomes narrow, and stable bonding may be difficult. On the other hand, when the Cu content Y exceeds 15.0% by mass, the amount of liquid phase generated at the solidus temperature (= eutectic temperature) increases, and the liquidus ratio becomes 35% from the solidus temperature. In some cases, the temperature range up to the temperature becomes narrow and stable bonding becomes difficult. A more preferable Cu content Y is 1.5 to 12.0% by mass.

  The Al-Cu alloy or Al-Cu-Mg alloy is composed of Si: 0.05 to 0.8 mass%, Fe: 0.05 to 1.0 mass%, Zn: 0.2 to 1.0 mass%. %, Mn: 0.1 to 1.8% by mass and Ti: 0.01 to 0.3% by mass may be further included. That is, Mg content is 0.5 mass% or less, or 0.2 mass% or more and 2.0 mass% or less, Cu: 0.7-15.0 mass% is contained as an essential element, Si: 0 0.05-0.8 mass%, Fe: 0.05-1.0 mass%, Zn: 0.2-1.0 mass%, Mn: 0.1-1.8 mass%, and Ti: 0.01 An aluminum alloy material composed of an aluminum alloy further containing one or more elements selected from ˜0.3 mass% as a selectively added element and the balance being Al and unavoidable impurities is also preferably used.

  When an aluminum alloy material made of such an Al—Cu alloy or Al—Cu—Mg alloy is joined as one joined member to the other joined member, the temperature T of one joined member at the time of joining is Cu. Depending on the content Y, it is preferable to control so that 660-15.6Y ≦ T ≦ 660-6.9Y and T ≧ 548. This achieves even better bonding.

I. Difference between solidus temperature and liquidus temperature In the joining step according to this embodiment, the difference between the solidus temperature and the liquidus temperature of the aluminum alloy material that produces the liquid phase is preferably 10 ° C. or more. When the solidus temperature is exceeded, liquid phase generation begins, but if the difference between the solidus temperature and the liquidus temperature is small, the temperature range in which the solid and the liquid coexist is narrowed, and the amount of the generated liquid phase is controlled. Difficult to do. Therefore, this difference is preferably set to 10 ° C. or more. For example, examples of the binary alloy having a composition satisfying this condition include an Al—Si alloy, an Al—Cu alloy, an Al—Mg alloy, an Al—Zn alloy, and an Al—Ni alloy. . Since the eutectic type alloy as described above has a large solid-liquid coexistence region, it is advantageous to satisfy these conditions. However, even with other alloys such as all solid solution type, peritectic type, and monotectic type, good bonding is possible because the difference between the solidus temperature and the liquidus temperature is 10 ° C or more. Become. Further, the above binary alloy can contain an additive element other than the main additive element, and substantially includes a ternary alloy, a quaternary alloy, and a multi-element alloy of more than five elements. For example, Al—Si—Mg, Al—Si—Cu, Al—Si—Zn, Al—Si—Cu—Mg, and the like can be given. Note that the larger the difference between the solidus temperature and the liquidus temperature, the easier it is to control the amount of liquid phase. Therefore, there is no particular upper limit for the difference between the solidus temperature and the liquidus temperature.

J. et al. Content of additive element in aluminum alloy material The content of the main additive element in the aluminum alloy material that generates a liquid phase can be set as follows from an equilibrium diagram in a binary system, for example. The joining temperature is T (° C.), the addition amount of the main additive element to aluminum is X (mass%), the eutectic temperature is Te (° C.), the solid solubility limit of the main additive element to aluminum is a (mass%), the eutectic crystal If the content of the main additive element at the point is b (mass%), a better liquid phase ratio can be obtained by performing the joining within a range satisfying the following formula (1). When the additive amount X of the main additive element is (0.05 / a + 0.95 / b) × (Te−660) × T + 660 or less, the amount of liquid phase generated in the aluminum alloy material is insufficient and joining becomes difficult. There is a case. On the other hand, if the additive amount X of the main additive element is (0.35 / a + 0.65 / b) × (Te−660) × T + 660 or more, the amount of the generated liquid phase is too large, resulting in a large shape change due to bonding. May occur. Therefore, it is desirable that the addition amount X of the additive element satisfies the following formula (1).

  (0.05 / a + 0.95 / b) × (Te−660) × T + 660 <X <(0.35 / a + 0.65 / b) × (Te−660) × T + 660 (1)

K. Crystal grain size after joining Normally, an aluminum alloy is deformed by a grain boundary slip that deviates at the crystal grain boundary in preference to plastic deformation of the crystal grain itself under high temperature and low stress. In particular, in the solid-liquid coexistence zone as in the bonding of this embodiment, the grain boundary is preferentially melted, and if the crystal grain size is small, the grain boundary in the unit volume increases and deformation due to grain boundary sliding occurs. It tends to occur. If the crystal grain size in the solid-liquid coexistence region is too small, grain boundary slip is likely to occur due to its own weight, and the shape change during heating may increase. Here, since it is difficult to directly measure the crystal grain size in the solid-liquid coexistence zone during bonding, the relationship between the crystal grain size in the solid-liquid coexistence zone during bonding and the crystal grain size after bonding heating I investigated. The crystal grain size when cooled in a normal brazing furnace cooling process (cooled to 400 ° C. at 30 ° C./min after heating) was measured, and this was set as the crystal grain size in the solid-liquid coexistence region during joining. . Next, the crystal grain size when held at the bonding heating temperature and then water-cooled was measured, and was defined as the crystal grain size after bonding heating. When both were compared, the crystal grain size was almost the same. Therefore, it can be said that the crystal grain size after bonding heating is equivalent to the crystal grain size in the solid-liquid coexistence region during bonding. Therefore, in this embodiment, the crystal grain size in the solid-liquid coexistence region during bonding is evaluated by the crystal grain size after heating. In the bonding step according to this embodiment, when the crystal grain size after heating is less than 50 μm, grain boundary slip is likely to occur due to its own weight, and if the bonding time is long, deformation of the members to be bonded may be promoted. Therefore, it can be said that the crystal grain size after heating is preferably 50 μm or more. The crystal grain size was measured by a cutting method based on JIS H: 501.

L. Bonding Method In the bonding process of this embodiment, the member to be bonded is basically heated in a furnace. There is no restriction | limiting in particular in the shape of a furnace, For example, the continuous furnace etc. which are used for manufacture of the batch furnace of a one-chamber structure, the heat exchanger for motor vehicles, etc. can be used. The atmosphere in the furnace is not limited, but is preferably performed in a non-oxidizing atmosphere as described above.

(Example 1)
An aluminum laminated structure having a three-dimensional flow path (hollow part) shown in FIG. 5B was produced using two types of Al—Si based alloys shown in Table 1 (alloys 1 and 2). For the production of the aluminum laminated structure, a casting method and machining were used in addition to the manufacturing method according to this embodiment and, as a comparative example, conventional methods such as brazing and diffusion bonding. Table 2 shows the results of manufacturing the laminated structure having the hollow portion. In Table 2 and Tables 3 and 4 to dictate, the target laminated structure was obtained, and the case where the flow path could be secured was indicated as “◯”, and the molding could not be performed or the shape including the hollow part was defective. The case where the occurrence of is shown as “×”. Here, in the manufacturing method, brazing, and diffusion bonding according to this embodiment, first, a plurality of plate materials having a length L of 100 mm, a width W of 50 mm, and a thickness t of 3 mm are prepared, and then a plurality of plate materials. In addition, a cutout portion 1 having a diameter φ of 5 mm is provided at a predetermined location by press punching, and a cutout portion 1 having a diameter φ of 80 mm is provided at a predetermined location on some plate materials instead of the diameter φ of 5 mm (see FIG. 5 (a)), a laminated structure having a height of 150 mm is manufactured by stacking 50 plate members having cutout portions (see FIG. 5B). A hollow portion is formed in the laminated structure by communicating cutout portions of the plate material. Specifically, as shown in FIG. 5, a plate material having a cutout portion having a diameter φ of 80 mm is disposed at the approximate center in the stacking direction, and a plate material having cutout portions having a diameter φ of 5 mm above and below the plate material. However, the laminated structure is formed in a shape in which the cutout portions are stacked so as to be aligned substantially vertically, and the two vertical flow paths are connected by a landing near the center as a hollow portion. Moreover, the hollow part shall be adjusted so that the full length may become a flow path of 180 mm.

Production examples 1 and 2 shown in Table 2 are production examples according to this embodiment for alloys 1 and 2 shown in Table 1, respectively. After holding, it was naturally cooled at room temperature. As production conditions, the nitrogen atmosphere was controlled at an oxygen concentration of 100 ppm or less and a dew point of −45 ° C. or less. The heating rate was 10 ° C./min at 520 ° C. or higher. In Production Example 1, a flux composed of KAlF ₄ is used, and in Production Example 2, no flux is used. Further, in Production Examples 1 and 2, no special pressurization was performed during heating, but a stress of about 0.01 MPa at the maximum was applied to the member to be joined due to the pressing load and weight of the jig. In Production Examples 1 and 2, the liquid phase oozes out to the joining surface during joining, so that the members to be joined are satisfactorily joined, and a laminated structure having a target hollow portion can be obtained.

  In Comparative Examples 1 and 2 shown in Table 2, a brazing method in which a non-corrosive flux is applied to Alloys 1 and 2 shown in Table 1 is used. A foil-like JIS 4043 brazing material having a length L of 90 mm, a width W of 40 mm, and a thickness t of 0.3 mm was disposed between the members to be joined so as to avoid the cutout portion. Brazing was carried out in an atmosphere in which nitrogen gas was passed as an inert gas in the furnace and the oxygen concentration in the furnace was adjusted to 20 ppm or less. The temperature of the laminate was measured, heated at a temperature rising condition such that the time until the temperature reached 600 ° C. was about 10 minutes, held at 600 ° C. for 3 minutes, then cooled and taken out of the furnace. . However, since the brazing material is deformed, the shape of the laminated body collapses after brazing, and the shape of the laminated structure cannot be maintained. In addition, there was a portion where the brazing material flowed out into the hollow portion and filled the hole of φ5 mm, and the target laminated structure could not be obtained.

  In Comparative Examples 3 and 4 shown in Table 2, diffusion bonding was used for Alloys 1 and 2 shown in Table 1, respectively. The plate material was washed with an organic solvent, laminated, and then placed in a vacuum furnace and heated. The heating condition was 545 ° C., which is 30 ° C. lower than the solidus temperature. After heating to a predetermined temperature, it was left for about 10 minutes and pressurization was started. The applied pressure was 3 MPa. After pressurizing for 60 minutes, the pressurization was released, the temperature was lowered to near room temperature by furnace cooling, and then the laminate was taken out from the furnace. However, the shape of the laminated body collapses after joining due to pressurization, or the joining of the members to be joined is insufficient, and the shape of the laminated structure cannot be maintained, and the desired laminated structure No body was obtained.

  In Comparative Examples 5 and 6 shown in Table 2, sand casting methods are used for Alloys 1 and 2 shown in Table 1, respectively. However, when the casting method is used, the hollow portion cannot be formed, and the target laminated structure cannot be obtained when any alloy is used. Further, Comparative Examples 7 and 8 shown in Table 2 are obtained by machining the alloys 1 and 2 shown in Table 1, respectively. As the manufacture of the structure by machining, an aluminum alloy block having a final shape having a length L of 100 mm, a width W of 50 mm, and a height H of 100 mm was prepared and cut by a precision MC processing machine. However, when machining was used, holes on the upper surface and the lower surface were obtained, but no cutting tool was inserted into the landing-like hollow portion provided in the intermediate portion, and machining was not possible. For this reason, the target structure was not obtained.

(Example 2)
Using an Al—Zn—Mg alloy (alloy 3) shown in Table 1, an aluminum laminated structure having a three-dimensional flow path (hollow part) having a shape shown in FIG. For the production of the aluminum laminated structure, a casting method and machining were used in addition to the manufacturing method according to this embodiment and, as a comparative example, conventional methods such as brazing and diffusion bonding. Table 3 shows the results of manufacturing the laminated structure having the hollow portion. Here, in the manufacturing method, brazing, and diffusion bonding according to this embodiment, a cutout portion 2 having a diameter φ of 3 mm is provided at a predetermined position by drilling a disk having a diameter φ of 100 mm and a thickness t of 5 mm ( A laminated structure having a height of 250 mm is manufactured by stacking 50 plate materials having cutout portions, as shown in FIG. A hollow portion is formed in the laminated structure by communicating cutout portions of the plate material. Specifically, by laminating the phase of the plate material (rotating the plate material) (see FIGS. 6B and 6C), a spiral flow path having a length of 700 mm is formed. It was supposed to be adjusted.

Production Example 3 shown in Table 3 is a production example according to this embodiment. The test piece was heated to 630 ° C. in a vacuum atmosphere, held at that temperature for 3 minutes, and then naturally cooled in a furnace. As manufacturing conditions, the vacuum atmosphere was controlled to 10 ⁻⁵ torr or less. The heating rate was 10 ° C./min at 520 ° C. or higher. In Production Example 3, no flux is used at the joint. In Production Example 3, the liquid phase oozes out on the joining surface during joining, so that the members to be joined are joined well and a laminated structure having a target hollow portion can be obtained.

  Comparative Example 9 shown in Table 3 uses a brazing method in which a non-corrosive flux is applied. A foil-like JIS 4043 brazing material having a diameter φ of 90 mm and a thickness t of 0.3 mm was disposed between the members to be joined so as to avoid the cutout portion. Brazing was carried out in an atmosphere in which nitrogen gas was passed as an inert gas in the furnace and the oxygen concentration in the furnace was adjusted to 20 ppm or less. The temperature of the laminate was measured, heated at a temperature rising condition such that the time until the temperature reached 630 ° C. was about 10 minutes, held at 630 ° C. for 3 minutes, then cooled and taken out of the furnace. . However, the Al—Zn—Mg alloy, which is Alloy 3, is unsuitable for the brazing method and cannot be brazed at all, and the desired laminate was not obtained.

  Comparative Example 10 shown in Table 3 uses diffusion bonding. The plate material was washed with an organic solvent, laminated, and then placed in a vacuum furnace and heated. The heating condition was 600 ° C., which is 30 ° C. lower than the solidus temperature. After heating to a predetermined temperature, it was left for about 10 minutes and pressurization was started. The applied pressure was 3 MPa. After pressurizing for 60 minutes, the pressurization was released, and the laminate was taken out of the furnace after the temperature became near room temperature by furnace cooling. However, the shape of the laminated body collapses after joining due to pressurization, or the joining of the members to be joined is insufficient, and the shape of the laminated structure cannot be maintained. Was not obtained.

  Comparative Example 11 shown in Table 3 uses a sand casting method. However, when the casting method was used, the spiral hollow portion could not be formed, and the desired laminated structure could not be obtained. Moreover, the comparative example 12 shown in Table 3 uses machining. As the manufacture of the structure by machining, a cylindrical aluminum alloy block having a final shape having a diameter φ of 100 mm and a height H of 250 mm was prepared and cut by a precision MC processing machine. However, when machining was used, the cutting tool did not enter the spiral hollow portion, and machining could not be performed. For this reason, the target structure was not obtained.

(Example 3)
Using an Al—Cu alloy (Alloy 4) shown in Table 1, an aluminum laminated structure having a three-dimensional flow path (hollow part) having the shape shown in FIG. This aluminum laminated structure simulates a rolling roll shape for performing roll processing while flowing a cooling or heating fluid. For the production of the aluminum laminated structure shown in FIG. 7, a casting method and machining were used in addition to the manufacturing method according to this embodiment and, as a comparative example, conventional methods such as brazing and diffusion bonding. Table 4 shows the results of manufacturing the laminated structure having the hollow portion. Here, in the manufacturing method, brazing, and diffusion bonding according to this embodiment, a cutout portion 2 having a diameter of 3 mm is provided at a predetermined position by drilling a disk having a diameter of 200 mm and a thickness of 5 mm, and a drill is provided. A hole 3 having a diameter of 30 mm is provided in the center (see FIG. 7A), and 60 sheets of cutouts are stacked to produce a laminated structure having a height of 300 mm. In the laminated structure, a phase was adjusted by rotating each plate material in the same manner as in Example 3 so that a spiral flow path having a length of 1000 mm was formed (FIG. 7B). (See (c)). Furthermore, in this laminated structure, the central hole communicates vertically and the central axis can communicate.

  Production Example 4 shown in Table 4 is a production example according to this embodiment. The test piece was heated to 605 ° C. in a nitrogen atmosphere, held at that temperature for 5 minutes, and then cooled at 4 ° C./min. And reheated at 300 ° C. for 5 minutes. The nitrogen atmosphere was controlled at an oxygen concentration of 100 ppm or less and a dew point of −45 ° C. or less. As a manufacturing condition, the heating rate was 10 ° C./min at 520 ° C. or higher. In Production Example 4, no flux is used at the joint. In Production Example 4, the liquid phase oozes out on the joining surface during joining, so that the members to be joined are joined well and a laminated structure having a target hollow portion can be obtained. Moreover, it became a high-strength laminated body by the heat processing after joining, and it was able to obtain the rolling roll shape for performing a roll process, flowing the cooling or heating fluid by inserting and fixing a shaft member.

  Comparative Example 13 shown in Table 4 uses a brazing method in which a non-corrosive flux is applied. A foil-like JIS 4043 brazing material having a diameter φ of 90 mm and a thickness t of 0.3 mm was disposed between the members to be joined so as to avoid the cutout portion. Brazing was carried out in an atmosphere in which nitrogen gas was passed as an inert gas in the furnace and the oxygen concentration in the furnace was adjusted to 20 ppm or less. The temperature of the laminate was measured, heated at a temperature rising condition such that the time until the temperature reached 600 ° C. was about 10 minutes, held at 600 ° C. for 3 minutes, then cooled and taken out of the furnace. . However, the Al—Cu alloy, which is Alloy 4, is unsuitable for the brazing method and cannot be brazed at all, and the desired laminate was not obtained.

  Comparative Example 14 shown in Table 4 uses diffusion bonding. The plate material was washed with an organic solvent, laminated, and then placed in a vacuum furnace and heated. The heating condition was 600 ° C., which is 30 ° C. lower than the solidus temperature. After heating to a predetermined temperature, it was left for about 10 minutes and pressurization was started. The applied pressure was 3 MPa. After pressurizing for 60 minutes, the pressurization was released, and the laminate was taken out of the furnace after the temperature became near room temperature by furnace cooling. However, the shape of the laminated body collapses after joining due to pressurization, or the joining of the members to be joined is insufficient, and the shape of the laminated structure cannot be maintained. Was not obtained.

  Comparative Example 15 shown in Table 4 uses a casting method using a sand mold. However, when the casting method was used, the spiral hollow portion could not be formed, and the desired laminated structure could not be obtained. Moreover, the comparative example 16 shown in Table 4 uses machining. As the manufacture of the structure by machining, a cylindrical aluminum alloy block having a final shape having a diameter φ of 200 mm and a height H of 300 mm was prepared and cut with a precision MC processing machine. However, when machining was used, the cutting tool did not enter the spiral hollow portion, and machining could not be performed. For this reason, the target structure was not obtained.

  In the structure manufacturing method of the embodiment described above, an aluminum alloy plate containing Mg within 0.5% by mass or 0.2% by mass to 2.0% by mass is used as a member to be joined, and the liquid of this aluminum alloy plate is used. Since a plurality of members to be joined are joined within a temperature range in which the mass ratio of the phase is 5% or more and 35% or less for 30 seconds or more and 3600 seconds or less, a solder material, a brazing material, a solution material, etc. are not used. Bonding can be performed with layer materials, and the size and shape change due to bonding can be reduced. Further, as compared with the case where diffusion bonding is used, pressurization is unnecessary, the time required for bonding can be shortened, and a special process for cleaning the bonding surface is not required. That is, the structure having a hollow portion can be easily manufactured by the structure manufacturing method of this embodiment. Further, by using a heat treatment type alloy as a member to be joined, the strength after joining can be ensured by solid solution hardening or precipitation hardening by performing heat treatment during cooling of joining or by reheating after cooling.

  In Examples 1 to 3 described above, a rectangular parallelepiped or disk-shaped aluminum alloy plate was used as the member to be joined, but the member to be joined should have a smoothness that does not cause a gap when laminated. Any shape such as thickness may be used.

  Further, the cutout portion may be obtained by cutting by various methods such as press punching, scissors, etching, laser processing, drilling processing such as drilling, etc., and any shape may be used.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and includes various modifications (including deletion of constituent elements) without departing from the scope of the present invention. ) Needless to say,

c1, c2 Si concentration T, T1-T3..Temperature Te, Ts2 Solidus temperature 1, 2, Cutout 3 Hole 4 Axis

Claims (3)

A method of manufacturing a structure having a hollow portion by laminating members to be joined,
A step of preparing an aluminum alloy plate having a magnesium content of 0.5% by mass or less and a cutout portion formed as at least a part of the members to be joined;
A plurality of the members to be bonded are stacked so that at least one of the adjacent members to be bonded becomes the aluminum alloy plate and the cutout portion communicates to form the hollow portion. and bonding a plurality of said workpieces ratio of the mass of the liquid phase is held within 3600 seconds 30 seconds to a temperature range 35% or less on 5% or more,
Only including,
In the step of joining the members to be joined, the maximum stress generated in the aluminum alloy material generating the liquid phase is P (kPa), and the ratio of the mass of the liquid phase generated in the aluminum alloy plate is V (%). Sometimes, the members to be joined are joined under the condition satisfying P ≦ 460-12 × V.
A structure manufacturing method characterized by the above. A method of manufacturing a structure having a hollow portion by laminating members to be joined,
A step of preparing an aluminum alloy plate having a magnesium content of 0.2% by mass or more and 2.0% by mass or less and having a cut-out portion formed as at least a part of the bonded members;
A plurality of the members to be bonded are stacked so that at least one of the adjacent members to be bonded becomes the aluminum alloy plate and the cutout portion communicates to form the hollow portion. A step of joining a plurality of the members to be joined in a temperature range in which the mass ratio of the liquid phase is 5% or more and 35% or less within 30 seconds to 3600 seconds;
Only including,
In the step of joining the members to be joined, the maximum stress generated in the aluminum alloy material generating the liquid phase is P (kPa), and the ratio of the mass of the liquid phase generated in the aluminum alloy plate is V (%). Sometimes, the members to be joined are joined under the condition satisfying P ≦ 460-12 × V.
A structure manufacturing method characterized by the above. In the step of preparing the member to be bonded, a disk-shaped member having the same shape having the cutout portion is prepared as the member to be bonded,
In the step of bonding the members to be bonded, the plurality of members to be bonded are stacked by shifting the phase of the cutout portions.
The method for producing a structure according to claim 1 or 2, wherein

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